1. Field of the Invention
The present invention relates to an information processing system, in particular, an image data processing system performing multiple services such as those of a printer, a copier, and a facsimile machine by a single machine, and, in particular, to an information processing system performing inter-process communications among a plurality processes for this purpose.
2. Description of the Related Art
In recent years, an image forming apparatus which holds therein facilities of respective apparatuses such as a printer, a copier, a facsimile machine, a scanner in a housing thereof (referred to as a composite machine). It is known that such a composite machine includes a display device, a printing device and an image-pickup device in one housing, and three sets of software are provided for respective ones of the printer, copier and facsimile machine. Then, by appropriately switching of these sets of software, the apparatus operates as the printer, copier, scanner or facsimile machine.